Basic red-violet dye and process of making same.



UNITE TATIES PAT NT .FFICE,

FRIEDRICH RUNKEL, OF ELBERFELD, GERMANY, ASSIGNOR TO FARBEN- FABRIKEN OFELBERFELD 00., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

BASIC RED-VIOLET DYE AND PROCE$S OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 689,025, dated December17, 1901.

Application filed August 17,1901.

(in which formula R means an alkyl radicalsuch as methyl, ethyl, or thelikeX a hydrogen atom, which can be substituted by a niethylic group)with the alkylated deriva- 5 tives of alpharnethylindol, (methylketole,)in which the imido-hydrogen is replaced by methyl or ethyl, described byE. Fischer,(see Annalen der Ohemz'c, Vol. 236, page 153, and 01.242,page 362,) and having the following 3 general formula:

(in which formula R means a methylic or an ethylic group.) In thisprocess the group NH 0 of the auramin is replaced by the radicals of themethyl or ethyl alpha-methylindols, the ammonium salt of the respectivemineral acid being formed as by-product, and the, salts of the bases ofthe newcoloring-matters are thus produced directly. The said newdyestuffs are in the shape of the mineral-acid salts, dark-brownpowders, which are readily soluble in water with a reddish-violet color,which Serial No. 72,426. (No specimens.)

is not essentially changed by the addition of dilute mineral acids. Theyare also readily soluble in alcohol with a reddish-violet color and aredissolved by concentrated sulfuric acid of 66 Baum with ayellowish-brown color. They dye cotton lnordanted with tannin, Wool, andsilk reddish-violet shades fast to the action of dilute mineral acidsand to the action of dilute caustic alkalies and ammonia.

In carrying out my new process practically I can proceed as follows, theparts being by weight: A solution prepared from fifteen parts of pureauramin G, having the formula:

and 7.3 parts of methyl-alpha-methylindol, having the formula:

\/ o on, ch,

in sixty-five parts of a thirty-per-cent. hydrochloric acid is heatedfor about from. one to two hours on a water-bath. The yellow color ofthe solution slowly turns brown. Subsequently it is stirred into aboutseven hundred parts of ice-water, which is mixed with about threehundred parts of a watery solution of common salt. By means of thisoperation the new dyestuff is separated in the shape of dark flakes. Itis filtered off, pressed, and dried at about from 80 to 90 centigrade.I'Vhen dry and pulverized, the new dyestuif thus obtained is adark-brown powder readily soluble in water and in alcohol with areddish-violet color. The color of the alcoholic solution is not changedby the addition of dilute alkalies. In concentrated sulfuric acid (of 66Baum) it is dissolved with ayellowishbrown color which is not changed bythe addition of a small quantity of ice, while a reddish-violet solutionis obtained on adding a larger quantity of ice.

The new coloring-matter dyes cotton mordanted with tannin, wool, andsilk clear reddish-violet shades fast to the action of dilute mineralacids and dilute alkalies.

The process proceeds in an analogous manner if in the above exampleethyl alphamethylindol (Pr n-ethyl-2-methylindol) or if another of theabove-mentioned auramins be employed.

The same dyestuffscan also be obtained by condensing the thio-ketones ofthe general formula:

(R meaning in this formula an alkyl radicalsuch as methyl, ethyl, or thelike-X meaning a hydrogen atom which can be substituted by a methylicgroup,) or the respective ketones with the abovesaid alkylatedderivatives of alpha-methylindol in the presence of mineral acids. Onperforming this reaction sulfureted hydrogen (orwater) is set free.

Having now described my invention and in what manner the same is to beperformed, what I claim as new, and desire to secure by Letters Patent,is-

1. The process for producing new basic dyestufis, which process consistsin first treating the auramins having the following general formula:

R meaning an alkyl radical and X meaning a hydrogen atom which can besubstituted by a methylic group, with derivatives of alphamethylindol inwhich the imido-hydrogen is replaced by an alkyl radical having thehereinbefore-described general formula:

in the presence of mineral acids and then isolating the resultingdyestuffs from the reaction mixture, substantially as hereinbeforedescribed.

2. The process for producing a new basic dyestufi, which processconsists in first treat ing the dyestufi having the following formula:

.With methyl-a1pha-methylindol having the formula:

' l \/|\N/ -01., C H

in the presence of mineral acids and then isolating the resultingdyestuif from the reaction mixture, substantially as hereinbeforedescribed.

3. The herein-described new basic dyestuffs being, when dry andpulverized, dark-brown powders readily soluble in water with areddish-violet color which is not essentially changed by the addition ofdilute mineral acids, also readily soluble in alcohol with areddish-violet color, being dissolved by concentrated sulfuric acid of66 Baum with a yellowish-brown color; dyeing cotton mordanted withtannin, wool, and silk reddish violet shades fast to the action ofdilute mineral acids, dilute caustic alkalies and ammonia, substantiallyas hereinbefore described.

4. The herein-described new basic dyestuff,

obtainable by condensing the dyestuff having mula in the presence ofmineral acids, being, when dry and pulverized, a dark-brown powderreadily soluble in water and in alcohol with a reddish-violet color, thecolor of the alcoholic solution being not changed by the addition ofdilute alkalies, being dissolved by concentrated sulfuric acid of 66Baum with a yellowish-brown color which is not changed by the additionof a small quantity of ice, while a reddish-violet solution is obtainedon adding a larger quantity of ice to the sulfuricacid solution; dyeingcotton mordanted with tannin, wool, and silk clear reddish-Violet shadesfast to the action of dilute mineral acids and dilute alkalies,substantially as hereinbefore described.

In testimony whereof I have signed my name in the presence of twosubscribing wit- FRIEDRICH RUNKEL. Witnesses:

Orro KoNIG, J. A. RIrrERsHAUs.

